Perspective Distortion from Interpersonal Distance Is an Implicit Visual Cue for Social Judgments of Faces

Ronnie Bryan,Ralph Adolphs,Pietro Perona

doi:10.1371/journal.pone.0045301

Abstract

The basis on which people make social judgments from the image of a face remains an important open problem in fields ranging from psychology to neuroscience and economics. Multiple cues from facial appearance influence the judgments that viewers make. Here we investigate the contribution of a novel cue: the change in appearance due to the perspective distortion that results from viewing distance. We found that photographs of faces taken from within personal space elicit lower investments in an economic trust game, and lower ratings of social traits (such as trustworthiness, competence, and attractiveness), compared to photographs taken from a greater distance. The effect was replicated across multiple studies that controlled for facial image size, facial expression and lighting, and was not explained by face width-to-height ratio, explicit knowledge of the camera distance, or whether the faces are perceived as typical. These results demonstrate a novel facial cue influencing a range of social judgments as a function of interpersonal distance, an effect that may be processed implicitly.

Highlights

We glean a wealth of socially relevant information from faces in the blink of an eye: gender, emotion, and whether a person is attractive, competent, threatening, or trustworthy, to mention a few
In Experiment 1a, faces photographed at the far distance elicited higher monetary investments in an economic trust game than those photographed at the close distance (Fig. 1a): mean investment difference was 3.262.45, t(17) = 2.78, p,0.02, with an effect size
The fact that viewers rated the far faces as closer suggests they may have been using a size heuristic to judge closeness, since the far faces are slightly wider than the close faces

Summary

Introduction

We glean a wealth of socially relevant information from faces in the blink of an eye: gender, emotion, and whether a person is attractive, competent, threatening, or trustworthy, to mention a few. Reliable judgments of trustworthiness can be made from faces viewed for 100 ms or less [1], and such judgments are found to influence real world behavior, such as voting [2], interest rates on person to person loans [3], and behavior in economic trust games [4] The widthto-height ratio of a face has been shown to be a reliable indicator of testosterone level and linked to untrustworthy behavior [6] Features such as the roundness of the cheeks and the large eye size (‘‘babyfacedness’’) may influence perceived trustworthiness by activating representations related to the perception of age [7]. Our approach expands the investigation from an analysis of the appearance of a face to an analysis of the relationship between a viewer and another person

Methods

Results

Conclusion